crypto/des/qud_cksm.c

   1 /*
   2  * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * From "Message Authentication" R.R. Jueneman, S.M. Matyas, C.H. Meyer IEEE
  12  * Communications Magazine Sept 1985 Vol. 23 No. 9 p 29-40 This module in
  13  * only based on the code in this paper and is almost definitely not the same
  14  * as the MIT implementation.
  15  */
  16 #include "des_locl.h"
  17
  18 #define Q_B0(a) (((DES_LONG)(a)))
  19 #define Q_B1(a) (((DES_LONG)(a))<<8)
  20 #define Q_B2(a) (((DES_LONG)(a))<<16)
  21 #define Q_B3(a) (((DES_LONG)(a))<<24)
  22
  23 /* used to scramble things a bit */
  24 /* Got the value MIT uses via brute force :-) 2/10/90 eay */
  25 #define NOISE   ((DES_LONG)83653421L)
  26
  27 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[],
  28                         long length, int out_count, DES_cblock *seed)
  29 {
  30     DES_LONG z0, z1, t0, t1;
  31     int i;
  32     long l;
  33     const unsigned char *cp;
  34     DES_LONG *lp;
  35
  36     if (out_count < 1)
  37         out_count = 1;
  38     lp = (DES_LONG *)&(output[0])[0];
  39
  40     z0 = Q_B0((*seed)[0]) | Q_B1((*seed)[1]) | Q_B2((*seed)[2]) |
  41         Q_B3((*seed)[3]);
  42     z1 = Q_B0((*seed)[4]) | Q_B1((*seed)[5]) | Q_B2((*seed)[6]) |
  43         Q_B3((*seed)[7]);
  44
  45     for (i = 0; ((i < 4) && (i < out_count)); i++) {
  46         cp = input;
  47         l = length;
  48         while (l > 0) {
  49             if (l > 1) {
  50                 t0 = (DES_LONG)(*(cp++));
  51                 t0 |= (DES_LONG)Q_B1(*(cp++));
  52                 l--;
  53             } else
  54                 t0 = (DES_LONG)(*(cp++));
  55             l--;
  56             /* add */
  57             t0 += z0;
  58             t0 &= 0xffffffffL;
  59             t1 = z1;
  60             /* square, well sort of square */
  61             z0 = ((((t0 * t0) & 0xffffffffL) + ((t1 * t1) & 0xffffffffL))
  62                   & 0xffffffffL) % 0x7fffffffL;
  63             z1 = ((t0 * ((t1 + NOISE) & 0xffffffffL)) & 0xffffffffL) %
  64                 0x7fffffffL;
  65         }
  66         if (lp != NULL) {
  67             /*
  68              * The MIT library assumes that the checksum is composed of
  69              * 2*out_count 32 bit ints
  70              */
  71             *lp++ = z0;
  72             *lp++ = z1;
  73         }
  74     }
  75     return z0;
  76 }